Antioxidants



ANTIOmANTS- Philip T. Paul, Naugatuck, Conn., assignor to United States Rubber Company, New York, N.- Y.. a corporation of New Jersey No Drawing. Application July 17, 1943.

j Serial No. 495,190

16 Claims. (Cl. 260-810) Thisinvention relates to a new class of antioxidants or age-resisters for organic substances which tend to deteriorate by absorption of oxygen from the air, e. g., rubber or allied gums, unsaturated fatty oils, such as unsaturated vegetable oils, essential oils, petroleum oils and their derivatives such as gasolines, soaps, aldehydes, synthetic resins, turpentine, insecticides such as digrris root, cube root and pyrethrum, and the l e.

According to the invention, the organic substance is incorporated with a chemical which is a dihydro dihydroiry naphthalene, the hydroxyl groups being ortho or para to one another.

The present chemicals may be synthesized from an ortho or para quinone and a conjugated diene by first reacting these chemicals to form Among the specific examples of the dihydro naphtho hydroquinones the following are included: 6-methyl 5,8-clihydro 1,4-naphtho hydroquinone (isoprenep-benmquinone); G-ethyl 5,8-dihydro 1,4-naphtho hydroquinone (Z-ethyl butadiene-p-benzoquinone); endo 5,8 -methylene 5,8-dihydro 1,4-naphtho hydrdduinone (1,3 cyclothe diene adduct and then isomerizlng the diene adduct. The'chemistry of the invention is welllznown, that is, it involves a Diels-Alder reaction -tween the duinone and the diene followed by isomerization, of the delta-hydrogen atoms to the orrygiens of the duinone, which is illustrated by the two reactions below:

delta 11 0 on 011W n Diels-Alder on ---o (an i i an J Am o g delta can on /O on 5 on Ice mu 5 1 g in! N 5 4 cm ims i on delta plary of the uinones, the following are included: i um o-benzo uinone, pp-chloro benzcquinone, p-bromcmm, Mia-w beuinone, p-dimethyl o-o uinone, p-methcm benzeis p-phenyl benzoquinone: and p-tertiary i l-benzoquinone. v

memplary oi the conjugated dienes which may be reacted with any of the above quinones are the-tolled: 1,3-butediene; 1,3 dimethyl 1,3- one; 1,3 cyclopentadiene; 2,3 dimethyl 1,3- ene: 2 phenyl 1,3:butadiene; 2 propyl 1,3-

and isoprene.

\ both-oi these forms are considered to be Within .i- 2 methow 1,3-butadiene; 1 vinyl 1,3- x H the scope of the invention.

The following examples are given to further illustrate the invention, the parts being by weight:

Butadiene (39 gr.) is bubbled into a suspension of 54 gr. p-benzo uinone in 400 cc. benzene in a pressure bottle. The bottle is sealed and the mixture allowed to stand a week. The bulk of the benzene is evaporated and the residue cooled and allowed to, crystallize.

The crudediene-quinone adduct is dissolved in /:a its weight of glacial acetic acid and 2 to 3 drops of 40% hydrobromic acid are added. An exothermic reaction follows which lasts a few minutes. 0n cooling, the reaction mixture sets to a paste. It is filtered. and recrystallized from ethyl acetate.

Melting range 210-211 C. (uncorrected). Alder et aL, Ber. 62, 2337 (1929) report a melting point of 212 C. for this material.

EXAMPLE 2-Pasrmwnon or 5,7-nmrnr1. 5,8-

nmrnao 1,4-mrnrno mnooumona A mixture c1 27 gr. freshly steam-distilled pm: ,1 uinone 83 gr. LS-dimethyl 134mm!- F. under soc pounds uer-eouore results being w follows:

one in so cc. beus'eue use olloweol to stood in a, bottle 2 days at room temperature. During the course of ii alloys is tote! oi approximately iii grams of material ouulycim; for on odduct or 2 mols 1,3-dimethyl i,3-=butooiiene to l moi p benzouuiuone seoorstecl cool was discarded. It melted at 13849? G.

l The mother-liquor from this moteriol is a. viscous yellowoll. It is .dissolveoi in on equal volum of glacial acetic eoiol cool a few drops of 40 hycixobromic amid. A vigorous exothermic reaction sets it which lasts a few miuutw. Aft er cooling, the reaction mixture is mixed with benzene and then washed with water. The beu- ,zenesolution is dried over sodium sulfate, snoi evaporated, the 1%t troceooi the benzene being removed under e. high vacuum. The resiciue on standing sets to e, clorls red brittle resin which as such is suitable for use in rubloer. The resin consists esseuhslly oi a, mixture of 5,"l=dimethyl fifi dihydro lA-uephthouumoue; i,e,e,o= tetra, hydro hhhutetrc, methyl mu uihyuroizy moses? st 212" I". and then mixedi on e mill with the usual compounding ingredients; cured end tensiied.

when finally compounded, the copolymer rub-.- ber stock is as follows; the parts being by weight:

Butadiene-styrene copolymer 10% Goal tar 5 Sulfur 2.0 Corbou block 50 Steam sold 23 Zinc oxide 5 Mercoptobenzothiezole (ccceleretor) 1.5 Antioxidant. 1W

The antioxidant stocks showed higher tensilee and elongotions thou the control stool: clthough the protective action was not as pronounced in the copolymer as in the ncturolrubber stock.

it is to bexuhclerstcod that other desires mling and compounding ingredients may be moor-- .poro-tecl clone with the preseivctivc, ior exemmethyl uic-clihyoroxyeuthrscene.

ple, there may be incorporated other oocelerotors, softeners, etc. 7 I

The antioxidant may be incorporated in any hype of rubber composition, such as those used for automobile tires and tubes, hose, belting,

' sheet and thread. rubber, rubberized fabrics,

To the above m-olihyuro he? nophtho hydroquiuoue ouol oil 1-1,. coco hydro i,i-=naphtho hydrocuiuoue are esiueol in- I the who oi 1.0 om to ice oi rubber. Cures ore metric for w, Ell oml u"; 231 e t 25 mucus persqusre inch steom pressure,

Unwed ieuefilee me momm 'r u .T E 'r E 10 2,120 m cm 103', 2,200 l 10s 2,360 083 cm. oaa c000 A 30 2,000 cs0 2,090; on emu no I The stocks are used in, oxyseu 32 hours at inch pressure, the

, osm um 5 mm;

we sum e, sq 3 quiuoue hyclmquinono 1 r u, "r m 'r itj'm sic 1,010 cs0 can an m 433 1,340 $66 I, 64$ co m i, coo cm 043 audelongotionswlexeiupercent.

A o! butollicneomi styrene-'iBuns" s)" is mixed with the oboveoutiozidaiits on o' iii theroisio o2 re pore ouflorzioout to 100.0

parts oomlymcr. m copolymr is used More pounds oouere molded goods, boots and shoes, etc, whether vulcanizeol in a mold, in open steam, in hot oir, or in the cold by the so-called acid process. The proportion of the antioxident'moy you from about 6.1% to 5%, although either'smoller or greater. proportions may be found useful, If the materiel to which it is added is o {liquid such. as rubber cement or on oil, the ouuiomdent may be dissolved therein in u suitable smell proportion. The antioxidant may be iucorporsteu into solid substances by milling or mastication,

who prepared for incorporotion into dispersions or solutions either in powder, paste or solution form, or applied in such iorms for incomorstiou by diiiusion, to the'surtcoe ofvulcouize'zi rubber goods. l v The term"u rubber" is employed. in the cloims todeflne o'vulceniusble elastic materiel which possesses high extensibility under loool oouhleoi with the property of flexibly museum; to w proximately its original size and shape ulcer the load is removed and includes indie. mbbei, buloim' outta perchs, and other. natural rubbers as well as synthetic vulcenmsble products such co poiy= chloroprene,'olefln polysulfides, butadieue poly= mere, umi modifle'dbutadienepolymeru (Buns 2i and Buns's), andthe like, which hove e flex-i loilityv and elasticity similar to rubber, end reclaims-endlatices of such material, which detenor-ate upousgeingflwhether or not ofimixed 3 a. A method comm-ding the with fillers, pigments, ;occelerev.ting agents, etc. Hayinwthua described my invention,'what I claim and desire to protect by Letters Petentis:

1. A method of retarding thede'terioration oi an organic substance which tends to deteriorate by absorptionof oxygen from thc'oir which'com J I prises incorporating therein 9135.8 dihydrmdihydroxy naphthalene in which the hydroxy groups belong to the class consisting ofortho, and i placement to each other iu the ncphthaiene nu- 3. L method, of retarding the deterioration of an organic substance which tends to deteriorate by absorption of oxygen from. the air which comprises incorporating therein u ,5,-8 dihydrolA-di warm naphthalene.-

oetericration 01':

an organic substance which tends to deteriorate by absorption of oxygen from the air which comprises incorporating therein a 5,8-dihydro dihydroxy naphthalene in which the dihydroxy groups are chosen for placement from the class consisting of the 1,2 and the 1,4 positions in the naphthalene nucleus.

4. A method of retarding the deterioration of an organic substance which tends to deteriorate by absorption of oxygen from the air which comprises incorporating therein a 5,8-dihydro 1,4-dihydroxy naphthalene.

5. A method of preserving a rubber composition which comprises incorporating therein a 5,8- dihydro dihydroxy naphthalene in which the dihydroxy groups are chosen for placement from the class consisting of the 1,2 and the 1,4 positions in the naphthalene nucleus.

6. A method of preserving a. rubber composition which comprises incorporating therein a 5,8- dihydro 1,4-dihydi'oxy naphthalene.

'7. A method of preserving a rubber composition which comprises incorporating therein a 5,8-dihydro dihydroxy naphthalene in which the dihydroxy groups are chosen for placement from the class consisting of the 1,2 and the 1,4 positions in the naphthalene nucleus.

8. A method of preserving a rubber composition which comprises incorporating therein a 5,8-dihydro 1,4-dihydroxy naphthalene.

9. A method of retarding the deterioration of an organic substance which tends to deteriorate by absorption of oxygen from the air which comprises incorporating therein 5,8-dihydro 1,4-dihydroxy naphthalene.

10. A method of retarding the deterioration of an organic substance which tends to deteriorate by absorption of oxygen from the air which comprises incorporating therein 5,7-dimethyl 5,8-dihydro 1,4-dihydroxy naphthalene.

hydro dihydroxy naphthalene in which the dihydroxy groups are chosen for placement from the class consisting of the 1,2 and the 1,4 positions in the naphthalent nucleus.

13. An organicsubstance which tends to deteriorate by absorption of, oxygen from the air containing a 5,8-dihydro dihydroxy naphthalene in which the dihydroxy groups are chosen for placement from the class consisting of the 1,2 and the 1,4 positions in the naphthalene nucleus.

14. A rubber composition containing a 5,8-dihydro dihydroxy naphthalene in which the dihydroxy groups are chosen for placement from the class consisting of the 1,2 and the 1,4 positions in the naphthalene nucleus.

15. An organic substance which tends to deteriorate by absorption of oxygen from the air containing 5,8- dihydro 1,4-dihydroxy naphthalene.

16. An organic substance which tends to deteriorate by absorption of oxygen from the air containing 5,7-dimethyl 5,8-dihydro 1,4-dihydroxy naphthalene.

' PHILIP T. PAUL. 

